Luminous tube



Sept. '27, 3932. J. GROSS 1,879,740

LUMINoUs TUBE l Filed Nov. 1928 INVENTQR Josep/1 E Grass.

BY i 4 ATTORNEY Patented sept. 27, 1932 Josmn n. Gnoss, or-swIfssvALn rnmisnvam AssIeNon To AURORA SIGN con:-

"rm, consonance: or PENNSYLVANIA Lumens 'man applicaties mea mvembr'a, is'zs. serial no; iexrov;

My invention relates to electricallyl operated `gas-filled luminous tubes and more particularly to electrodes for such tubes.

It is the object of my invention, in general to provide a luminous tube that shall be sim-v ple and eicient in operation and capable ot' being Areadily andy economically manufactured and maintained.A i

Aimore `specic object of myinvention is lo to provide a luminous tube in whichI `a minimum amount of sputtering-will occur during its operation. Another object of my invention is to provide a luminous tube in .which the disintegras tion of the electrodes shall be practically nevligible. l A I It is also an object of my, invention. .to provide a luminous tube that may be operatedby a minimum amount of auxiliary apparatus` Other objects of the invention will, in part,

be. obvious, and willin part, appear herein'- after. l

For an illustration of one-otl the various forms my invention may take, reference may be had to the accompanying drawing, in which;` s

Figure 1 is a top plan view, partially broken away, of a luminous tube embodying my.

invention 80 of Fig. 1

Fig. 3 is a view takenA along the4 line' III--III- of Fig. 1; and

Fig. 4 is a view taken along the line IV-IV of Fig. 1. v

In the drawing, I have illustrateda lumiy nous tube as comprising an elon ated-sealed glass envelope 1 that is adapte to be'ex-l hausted of air and gases toa predetermined value and then filled with a predetermined v amount of amonatomic gas such as neon, ar-

gon or helium.

The glass envelope 1 is provided with enlarged end portions 2 and 3 in which are disposed, respectively, a cathode 4 and aan-anode Fig. 2 is a view taken along the'line Il--II 5, both of these electrodes being-,connected to the seconda circuit of a transformer a pair of lea -in wires 7 and 8.

As; shown, the cathode 4 is disposed -in an elongated cavity 9in a' supporting member 10. of. a suitable insulating material, such as porcelain. 1 The.. porcelain member 10 is mounted on and: fusedto a glass-press 11 that constitutes'a` part ofthe glass envelope 1. I' A conductor 12 that is disposed in a lon tudi-v e.. nal aperture inthe supporting mem er.10A

serves to connect wirel 7. f Y g It will be noted thatthe cavity 9 isof such shap'eand. dimensions thatxth'e,v memberk 10 the cathode 4 to the lead-in covers-.the cathode 4 to such any extentthat'4 only a smallarea of its total'fsurface is exif posed and `therefore that the member 10 not`V only acts-asa support for the cathode but also y serves as an insulating cover or `casing' 'to'limit or restrict the surface of thecathode that is exposed lto the gas with which the lamp may be filled. This provision'for covering the cathode by an' insulating material to such an extent that only a small portion of its entire surface is exposed is important, in that it limits thearea of the cathode from whichvthe electricalfdischarge may pass when the tube is placed in operation, and therefore conserves the heat in the cathode to such a degree while the tube is being started that itis not necessary to employ a heater for the cathode or a large kindling current. I have found that the exposed area of the electrode/should be at least less than one square decimeter per ampere.

, I-havev also found'that especially eilicient l and suitable salts, such as barium carbonate and strontium carbonate. While the materials referred to may be emplo ed in various combinations, I prefer to emp oy a mixture' of `approximately the following proportions, by weight, nickel 50 percent, barium carbonate .percent and strontium carbonate 25 percent. The ingredients'are mixed together l thoroughly and then -tamped into the cavity passageway through which any dischargev from the cathode must pass. l

I cavity 9 of the member 10, it is strongly".- heated until it becomes a sintered mass of.

`After the mixture is tamped down in the nickel, barium` oxide, and strontium oxide. Upon completion of the sintering process, the

`supporting member 10 carrying the cathode 4 andthe press 11, upo'n which it is mounted, are placed in position in the tube and the press is fused to the glass envelope 1.

Any suitable electrode may be employedas the anode 5 in the tube, but I prefer to use an lanode constructed in the same manner as the cathode just described, as it simplifies the manufacturing activities necessary to produce a satisfactorily operative tube.

After the anode-and the cathode are placed in position in the glass envelope, the tube may be exhausted, filled with gas and .sealed oii' inthe usual manner. v

Upon operatively connecting the completed tube to a. suitable source of 'electrical energy,- such as the transformer 6, the voltage risesrapidly for a small fraction of a second until lthe breakdownA of the gap between thev electrodes occurs. After the breakdown occurs, the voltage drops to a value determined by the size of the tube and the electrodes. Inasmuch as the exposed surface of the cathode 4 is very limited, the discharge is restricted to `such a small area that it heats rapidly to such 'a degree as effects a discharge of -electrons from that surface and thereby causes the gas in the tube to become luminous.-

By reason of the small exposed area. of the cathode and the short period during whichy the voltage rises, such disintegration of the 1 tured, that is simple in operation and' which I will have exceptionally long life. l

While I have illustrated and described only one specific embodiment of .my invention, I realize that it is susceptible of wide application, and Ido not desire to be limited to the precise construction illustrated and described.

I claim as my invention:

1. An electron emissive electrode for luminous tubes comprising` a lead-in conductor embedded in asintered mass of nickel, barium oxide and strontium oxide.-

2. An electron emissive electrode for luminous tubes comprising a ylead-in conductor having one endA thereof embedded in a sintered mass of nickel, barium oxide andstrontium oxide.v

3. An electron emissive electrode for lum1- fnoustubes comprising a refractory non-metallie. sleeve, a lead-in conductor having an end extending into the sleeve, and a sintered compact mass of nickel, barium oxide and ,strontium oxide in the sleeve, said mass being fusedto the sleeve and lead-in conductor.

4. An electron emissive electrode for luminous tubes comprising a lead-in conductortrode comprising a lead-in conductor, and 4a homogeneous mass of approximately the proportions by weight, `nickel 50 percent, barium oxide 25- per cent and strontium .oxide 25 percent,l said mass being fused to an end portion of the lead-in conductor that extend-s into the. press end of the tubes.

7. The method of making electron emissive electrodes for luminous tubes that comprises filling a hollow refractory -sleeve with a mixture of nickel, barium carbonate and strontium carbonate, tamping said mixture and then heating `the. sleeve and mixture to form a sinteredv mass of nickel, barium oxide and str ontium oxide. f

8. The method of making electron emissive electrodes for luminous tubes that comprises inserting a lead-in conductor into a sleeve,l filling a portion of said sleeve with a mixture of nickel, barium carbonate and strontium carbonate, compacting said mix` ture inthe sleeve and about the Alead-in conductor, and lheating theumixture to form a sintered mass of nickel, barium oxide and strontium oxide.

9.v An electron emissive electrode for luminous tubes comprising a lead-in conductor and a sintered mass of one or more alkaline earthsand a non-oxidized metal of the ferrous group fused to said conductor.

im. 192s.`

' JOSEPH ny GROSS. 

